Exterior adjustment metering jet insert plate for carburetors and carburetor modifying method

ABSTRACT

An insert block or plate for disposition between the horizontally inwardly opening flow chamber cover of a carburetor and that face of the associated carburetor body portion against which the cover is conventionally secured in order to define a flow chamber of the carburetor. The insert plate or block is so constructed and mated with the conventional main metering jet mounting portion of the carburetor body which is conventionally closed by the flow chamber cover so as to define an extension of the conventional fuel metering passage controlled by a replaceable metering jet, which jet is removed to enable installation of the insert plate. In addition, the insert plate includes an adjustable metering valve for metering the flow of fuel through the extension of the fuel metering passage and the adjustable metering valve is adjustable from the exterior of the carburetor in a manner which does not required the removal of any part of the carburetor and which may be carried out during the operation of an associated internal combustion engine.

United States Patent [191 Johnson EXTERIOR ADJUSTlVIENT METERING JET INSERT PLATE FOR CARBURETORS AND CARBURETOR MODIFYING METHOD [76] Inventor: Harley D. Johnson, 4228 26th St.

W., Bradenton, Fla. 33506 [22] Filed: Jan. 2, 1973 [21] Appl. No.: 320,118

Primary Examiner-Tim R. Miles Attorney, Agent, or FirmClarence A. OBrien &

- Harvey B. Jacobson 1 Apr. 30, 1974 ABSTRACT An insert block or plate for disposition between the horizontally inwardly opening flow chamber cover of a carburetor and that face of the associated carburetor body portion against which the cover is conventionally secured in order to define a flow chamber of the carburetor. The insert plate or block is so constructed and mated with the conventional main metering jet mounting portion of the carburetor body which is con ventionally closed by the flow chamber cover so as to define an extension of the conventional fuel metering passage controlled by a replaceable metering jet, which jet is removed to enable installation of the insert plate. In addition, the insert plate includes an adjustable metering valve for metering the flow of fuel through the extension of the fuel metering passage and the adjustable metering valve is adjustable from the exterior of the carburetor in a manner which does not required the removal of any part of the carburetor and which may be carried out during the operation of an associated internal combustion engine.

5 Claims, 17 Drawing Figures EXTERIOR ADJUSTMENT METERING JET INSERT PLATE FOR CARBURETORS AND CARBURETOR MODIFYING METHOD arh .retom n rusuqns have been s sysbaqitq the extent that efficient engine operation is possible under moderately varying atmospheric conditions power output. Such carburetors are, of course, wholly acceptable to the general automotive industry in that they are reasonably reliable, efficient and economical. g.

However, when maximum power output is desired under precise atmospheric conditions, it is mandatory that precise controls with regard to the main metering of liquid fuel be provided. Accordingly, adjustable main metering jets are more desirable in carburetors utilized for racing than fixed aperture jets. In addition, ease of the adjustment of adjustable jets is a very important feature inasmuch as atmospheric conditions at the site of an automobile race may change sufficiently prior to the beginning of the race or even during the race to adversely affect the maximum power output of engines used in racing. Consequently, a carburetor equipped with externally adjustablemain metering jets as opposed to internally mounted fixed metering jets wh n es aat d sm y by eartialsiisasssmbly 9f the associated carburetor is preferred. However, certain stock carburetors which have been found to be desirable for racing purposes are not equipped with externally adjustable main metering jets but instead with internally mounted replaceable fixed jets.

It is accordingly the main object of this invention to provide a means by which a conventional carburetor equipped with internally mounted replaceable fixed jets but otherwise well suited for racing purposes may be modified so as to be provided with externally adjustable metering jets in place of its replaceable internally mounted fixed jets.

Another object of th invention, in accordance with the immediately preceding object, is to provide an assemblage for converting a fixed jet carburetor to an externally adjustable metering jet carburetor with a minimum of effort and expense.

A further important object of this invention is to provide a method of converting a fixed jet carburetor toan externally adjustable metering jet equipped carburetor that may be followed with regard to several different models of existing carburetors.

A final object of this invention to be specifically enumerated herein is to provide an apparatus for converting a carburetor equipped with internally mounted replaceable fixed metering jets to a carburetor utilizing externally adjustable main metering jets and which will conform to conventional forms of manufacture, be of simple construction and easy to install so as to provide a device that will be economically feasible, long lasting and installable at a race site.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a top plan view of a conventional form of carburetor equipped with two primary venturies and two secondary venturies with a choke valve disposed above and primary venturi passages.

FIG. 2 is an enlarged fragmentary vertical sectional view taken substantially upon the plane indicated by the section line 2-2 of FIG. 1 and illustrating the outer face of the insert plate by which the carburetor of FIG. 1 has been converted to a carburetor provided with externally adjustable main metering jets.

FIG. 3 is a fragmentary horizontal sectional view taken substantially upon the plane indicated by the section 33 of FIG. 2 and illustrating the manner in which the insert plate serves to form an extension of the fuel metering passages the carburetor leading from the flow chamber to the venturi passages.

FIG. 4 is a fragmentary vertical sectional view taken substantially upon the plane indicated by the section line 4--4 of FIG. 2 and illustrating the operative association of one of the adjustable metering jets of the instant invention with the corresponding fuel passage extension.

FIG. 5 is an enlarged fragmentary vertical sectional view taken substantially upon a plane passing through the center line of the adjustable metering jet illustrated in FIG. 4 but disposed at 90 relative to the section line 4--4 of FIG. 2.

FIG. 6 is an exploded perspective view of one of the insert plates of the instant invention.

FIG. 7 is a fragmentary perspective view illustrating the conventional mounting of removable fixed aperture jets in the inlet ends of the carburetor body fuel metering passages.

Referring now more specifically to the drawings, the numeral 10 generally designates a conventional form of four-barrel carburetor. The carburetor 10 includes a first pair of secondary venturi passages 12 extending through the main body 14 of the carburetor 10 and a second pair of primary venturi passages (not shown) are disposed beneath the conventional choke valve 16. In addition, the carburetor body 14 includes opposite faces 18 and 20 over which flow chamber defining horizontally inwardly opening curves 22 and 24 are conventionally secured by means of fasteners 26.

With reference now more specifically to FIGS. 3 and 7 of the drawings, a pair of internally threaded inlet ends of fuel metering passages 28 open outwardly through each of thefaces 18 and 20 and into the flow chambers 30 defined within the covers 22 and 24. Further, it may be seen from FIG. 7 of the drawings that through-board main metering jets 32 are conventionally removably threadedly engaged in the inlet ends 28.

However, in practicing the instant invention, a framelike plate referred to in general by the reference numeral 34 is inserted between each of the faces 18 and 20 and the corresponding covers 22 and 24 with each plate 34 disposed in fluid-tight sealed engagement with the corresponding side face of the carburetor body 14 and each cover engaged with the corresponding plate 34 in a fluid-tight manner, the through-bored main metering jets 32 having been removed before insertion of the plates 34 between the covers 22 and 24 and the body 14.

Each of the plates 34 includes a pair of integral bosses 36 disposed within the confines of the peripheral portions of the plates and each boss has a sleeve 38 associated therewith. The ends of the sleeves 38 remote from the bosses 36 are anchored to the upper peripheral member 40 remote from the bosses 36 and the sleeves 38 define upstanding bores 42 which open outwardly through the peripheral members 40. The lower ends of the bores 42 open into transverse bores 44 ex tending laterally through the lower ends of the sleeves 28 and the transverse bores 44 open into through bores 46 formed through the bosses 36. The bores 42 are internally threaded as at 48 intermediate their upper and lower ends and threaded main metering jets 50 are threadedly engaged in the threaded portions 48 of the bores 42 and include slotted upper and heads 52 to which access may be had through the upper ends of the bores 42.

The bosses 36 include outwardly projecting nipples 54 which are disposed in the inlet ends of the passages 38 and the bosses 36 are radiused as at 56 about the base ends of the nipples 54 to form annular seats for O- ring seals 58.

From FIG. 3 of the drawings it may be seen that O- ring seals 58 form fluid-tight seals between the bosses 36 and the portions of the body 14 through which the inlet ends of the fuel metering passages 28 open. Also, from FIGS. 4 and of the drawings, it may be seen that the lower ends of the metering jets 50 project outwardly into the inner sections of the bores 42 and the bores 44. In this manner, the metering jets 50 may be utilized to meter the liquid level flowing from the flow chambers 30 through the bores 44 and into the bores 46. Further, from FIG. 1 of the drawings it will be noted that the upper end heads 52 of the metering jets 50 may be readily engaged by a thin screw driver from the upper side of the carburetor 10.

Of course, the plates 34 may be either fabricated from a plurality of machined parts secured together in order to form the plates, or the plates 34 may be roughcast and then machined into final form. In addition, the plates 34 may be produced by molding processes.

The plates 34 have been specially designed for use in conjunction wit Holly carburetors. However, it is also possible to incorporate the basic concept of the invention in the construction of other carburetors. As an example, the carburetor includes a metering block 64 inwardly of each plate 34 and comprising the opposite sides of the body 14. The covers 22 and 24 are conventionally secured against these metering blocks 64 and it is possible to incorporate the externally adjustable main metering jet principle of the instant invention in the metering blocks 64. However, the plates 34 may be utilized in addition to the metering blocks 64 in order to successfully practice this invention on both factory installation and after market installations at a nominal cost.

By utilizing the plates 34 in order to provide a means whereby the fuel passing into the through passages 28 may be adjustably metered and adjustment of the metering process may be accomplished from the exterior of the carburetor 10 without involving assembly of any carburetor part and while the associated combustion engine is in operation, precise fuel metering adjustments may be made according to existing atmospheric conditions in order to obtain the maximum horse power possible from the associated combustion engine.

modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. The method of modifying, for external metering jet adjustment capability, a carburetor of the type including a body portion having an outer surface through which the inlet end of a flow passage opens and with the inlet end of the passage having a removable through-bored metering jet secured therein and an open sided cover defining a float chamber removably secured over said body portion with the edges of said cover defining the open side thereof disposed in fluidtight sealed engagement therewith; comprising the steps of removing said cover, removing said jet, inserting a spacer plate between sid outer surface and the open side of said cover, said spacer plate including a portion thereof for closing said inlet end, said portion including a fuel passage extending therethrough including an inlet opening outwardly of the cover side of the plate within the confines of the interior of said cover and an outlet end opening into said flow passage inlet end, said plate further including a needle valve passage having one outer end opening exteriorly of said plate through one edge portion thereof between the opposite side faces of said plate and an inner end intersecting with said fuel passage intermediate its opposite ends, and an elongated needle valve disposed in and lengthwise operable to said needle valve passage to variably restrict the effective flow capacity of said fuel passage adjacent the intersection of said needle valve passage therewith, said method further comprising the step of securing said cover and plate to said body with said plate sealed against said outer surface and the open side of said cover sealed against said plate.

2. In combination with a carburetor of the type including a body portion having an outer surface through which the inlet end of a flow passage opens and with the inlet end of the passage having a removable through-bored metering jet secured therein and an open sided cover defining a float chamber removably secured over said body portion surface with the edges of said cover defining the open side thereof disposed in fluid-tight sealed engagement therewith; an insert spacing plate sealingly insertable between said cover and body after removal of said cover and metering jet, said plate including first passage means defining an extension of the inlet end of said flow passage and second passage means intersecting with said extension at one end and opening outwardly of one marginal edge portion at the other end, and an elongated needle valve sealingly disposed in said second passage means for longitudinal shifting therein and including an inner end portion operable to invaribly throttle fuel passing through said extension at its intersection with said second passage means in response to longitudinal shifting of said needle valve in said second passage means.

3. The combination of claim 2 wherein said needle valve is threadedly engaged in said second passage mans and includes a non-circular physical portion at its outer end adapted to be engaged by a hand tool inserted into said other end of said second passage means.

4. The combination of claim 3 wherein said plate is constructed of rigid material and is in the form of a frame-like member with only those portions of said plate defining said first and second passage means being disposed within the peripheral portions of said plate.

5. The combination of claim 4 wherein said carburetively associated with said flow passage inlet ends. 

1. The method of modifying, for external metering jet adjustment capability, a carburetor of the type including a body portion having an outer surface through which the inlet end of a flow passage opens and with the inlet end of the passage having a removable through-bored metering jet secured therein and an open sided cover defining a float chamber removably secured over said body portion with the edges of said cover defining the open side thereof disposed in fluid-tight sealed engagement therewith; comprising the steps of removing said cover, removing said jet, inserting a spacer plate between sid outer surface and the open side of said cover, said spacer plate including a portion thereof for closing said inlet end, said portion including a fuel passage extending therethrough including an inlet opening outwardly of the cover side of the plate within the confines of the interior of said cover and an outlet end opening into said flow passage inlet end, said plate further including a needle valve passage having one outer end opening exteriorally of said plate through one edge portion thereof between the opposite side faces of said plate and an inner end intersecting with said fuel passage intermediate its opposite ends, and an elongated needle valve disposed in and lengthwise operable to said needle valve passage to variably restrict the effective flow capacity of said fuel passage adjacent the intersection of said needle valve passage therewith, said method further comprising the step of securing said cover and plate to said body with said plate sealed against said outer surface and the open side of said cover sealed against said plate.
 2. In combination with a carburetor of the type including a body portion having an outer surface through which the inlet end of a flow passage opens and with the inlet end of the passage having a removable through-bored metering jet secured therein and an open sided cover defining a float chamber removably secured over said body portion surface with the edges of said cover defining the open side thereof disposed in fluid-tight sealed engagement therewith; an insert spacing plate sealingly insertable between said cover and body after removal of said cover and metering jet, said plate including first passage means defining an extension of the inlet end of said flow passage and second passage means intersecting with said extension at one end and opening outwardly of one marginal edge portion at the other end, and an elongated needle valve sealingly disposed in said second passage means for longitudinal shifting therein and including an inner end portion operable to invaribly throttle fuel passing through said extension at its intersection with said second passage means in response to longitudinal shifting of said needle valve in said second passage means.
 3. The combination of claim 2 wherein said needle valve is threadedly engaged in said second passage mans and includes a non-circular physical portion at its outer end adapted to be engaged by a hand tool inserted into said other end of said second passage means.
 4. The combination of claim 3 wherein said plate is constructed of rigid material and is in the form of a frame-like member with only those portions of said plate defining said first and second passage means being disposed within the peripheral portions of said plate.
 5. The combination of claim 4 wherein said carburetor body portion includes a pair of flow passage inlet ends opening through said outer surface, said plate including a pair of said first passage means, a pair of second passage means and a pair of needle valves operatively associated with said flow passage inlet ends. 